This invention relates generally to stabilizers for rear tipping dumping vehicles. More particularly, the instant invention relates to stabilizer apparatus adapted to independently level the lowest side of the dumping vehicle during the unloading operation.
As will be well recognized by those skilled in the art, dumping vehicles comprise a cargo or platform structure pivotally coupled to the chassis frame about an axis substantially parallel to the axle of the rear trailer wheels. A normal rear dumping vehicle has a chassis resiliently supported by at least one rear axle and a dump body pivotally mounted on the chassis. The dump body is pivotally mounted about an axis parallel to at least one rear axle or about the axle itself. Since the chassis is resiliently supported, usually by leaf springs, the chassis and dump body often become unstable when the dump body is being dumped, which is especially true of very long dump bodies, or on laterally sloping terrain. The springs allow the dump body to move laterally with respect to at least one wheeled rear axle. When the load is to be dumped, the platform is raised upwardly so that the load may be deposited at a designated location. However, as the loaded cargo platform is raised, the center of gravity of the dumping unit also rises so that mechanical stability of such unloading vehicles during the dumping operation can be critical. This is particularly true since the wheels of the vehicle seldom rest upon a flat area, and if the terrain or supporting surface is too uneven, tipping of the vehicle may result.
Accordingly, a variety of approaches have been taken in the prior art to stabilize vehicles during the unloading operation. One prior art solution for stabilizing dumping vehicles includes apparatus adapted to lock the rear suspension of the trailer in a predetermined position to prevent tipping as the trailer platform rises. Examples of this concept are shown in U.S. Pat. Nos. 3,778,105; 2,999,721; and 2,662,780. The use of hydraulic piston systems for leveling tilting bodies is shown generally in U.S. Pat. Nos. 3,044,832; 3,083,059 and 2,381,425. U.S. Pat. Nos. 2,829,901; and 3,362,299 disclose multi piston systems whereby truckbeds and the like may be leveled by actuating various control valves. U.S. Pat. No. 3,331,616 discloses a system whereby a vehicle (not a tilting unloading dumping vehicle) may be maintained relatively level automatically as it is loaded with increased weight.
None of the known prior art systems provide a means for automatically leveling the tilt bed of a dumping vehicle in response to an unlevel condition during unloading. Although hydraulic piston arrangements are depicted in the prior art, these must be constantly manipulated by the operator to properly balance the unloading vehicle.